Testing the Addition of M3814 (Peposertib) to Radiation Therapy for Patients With Advanced Head and Neck Cancer Who Cannot Take Cisplatin

This phase I trial investigates the side effects and best dose of peposertib when given together with radiation therapy in treating patients with head and neck cancer that has spread to other places in the body (advanced) who cannot take cisplatin. Peposertib may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth. Radiation therapy uses high energy x-rays to kill tumor cells and shrink tumors. This trial aims to see whether adding peposertib to radiation therapy is safe and works well in treating patients with head and neck cancer.